Alkyl esters of fatty acids in fuel microemulsions for the internal combustion engine and for oil furnaces

ABSTRACT

Alkyl esters of Fatty Acids such as methyl stearate are valuable renewable energy resources that can be used to replace in part petroleum products such as diesel oil and fuel oil for furnaces. Microemulsion fuels made by blending diesel oil at low shear with an Additive containing the ester result in stable compositions at sub-freezing temperatures and also, have advantages of good engine performance and abatement of pollution. Compositions of diesel oil/Additive plus Fatty Acids Esters at 95/05, 90/10, 80/20, 70/30 and 60/40 weight/weight were investigated. The utilization of the alkyl esters of the fatty acids depends on the particular unsaturated fatty acid used in the Additive, the fuel composition and the particular ester. Summaries in graph form show how several esters of fatty acids are used in the microemulsion fuels both for diesel oil used in the internal combustion engine and heating oil for furnaces.

BACKGROUND

[0001] Microemulsion fuel compositions for the internal combustion engine and for oil furnaces are described in Steinmann's U.S. Pat. No. 6,017,368. Formulations described in this patent involve the use of unsaturated fatty acids with the condition that the percent of saturated fatty acids such as stearic and palmitic acids total less than about 10%. This condition is necessary in order to achieve stable microemulsions.

[0002] The concept in this invention is to use the alkyl esters of fatty acids in micooemulsion fuels. Valuable esters of saturated fatty acids such as methyl stearate, methyl palmitate and methyl myristate are included. There is an abundant renewable source of the saturated fatty acids present as glycerides in many plants and also in animal fats. Examples of vegetable oils containing these saturated fatty acids are coconut oil, cottonseed oil, palm oil and palm kernal oil. Examples of animal oils and fats containing these saturated fatty acids are lard, beef tallow, fish oil and even reclaimed cooking oil.

[0003] A primary objective of this invention is to utilize this abundant renewable source for the partial replacement of petroleum. However, these oils and fats are present as glycerides and unfortunately, glcerides cannot be used directly in fuel compositions because they have poor combustion characteristics accompanied by excessive air pollution by the exhaust gases of the internal combustion engine and in the stack gases from oil furnaces. Also they do not run clean in the internal combustion engine so that eventually their use will give problems in engine performance. Since the free saturated fatty acids can only be used to a minor extent (a total of less than 10%), the only alternative is to use the esters of the fatty acids such as methyl stearate, methyl palmitate and methyl myristate in the microemulsion fuels.

[0004] The esters are manufactured either by esterification of the fatty acids or by the transesterification of the glycerides with an alcohol such as methanol. In the transesterification of the glcerides, glycerine is a by-product. For example, transesterification with methanol gives the methyl esters, transesterification with ethanol gives the ethyl esters and transesterification with butanol gives the butyl esters of the saturated fatty acids. Kawahara et al. in U.S. Pat. No. 4,164,506 describes a process of making these esters from unrefined fats and oils. This patent is an example that the manufacture of the esters of the fatty acids is already established technology. The present invention deals only with how the esters of the saturated fatty acids are used in microemulsion fuels for the internal combustion engine and for heating oils.

[0005] Esters of fatty acids have been reported to be used as solutions in diesel oils. They are very soluble in diesel oil and fuel oil. However, there are several disadvantages in using these solutions which are:

[0006] 1. They gel to a solid below the freezing point of water. Therefore, the solutions are difficult to use in cold climates resulting in unsatisfactory transport of them in fuel lines.

[0007] 2. Combustion of them gives high particulate matter in the exhaust. In order to reduce the particulate matter one must increase the air/fuel ratio but then this increases the oxides of nitrogen (NOx).

[0008] 3. There is very little tolerance for water in the solutions. Therefore, any contamination of the solutions with water may cause phase separation which would be a problem in the fuel tanks and the transport lines.

[0009] 4. Since there is very little tolerance for water in the solutions, there is no way to neutralize sulfur acids generated from the oxidation of residual sulfur in the diesel oil.

[0010] It was discovered that all of the four disadvantages described above can be overcome by utilizing the esters of fatty acids in microemulsion fuels using the teachings of U.S. Pat. No. 6,017,368.

SUMMARY OF THE INVENTION

[0011] The primary objective in this invention is to expand the use of renewable energy resources to further replace petroleum. The expansion is represented by the use of the alkyl esters of fatty acids in microemulsions such as methyl stearate and methyl palmitate.

[0012] A second objective is the utilization of the esters of fatty acids in microemulsions in which the compositions are stable at sub-freezing temperatures. The criterion is that they must be fluid with low viscosity and be uniform at −15° C. completely free of gels.

[0013] A third objective is the utilization of the esters of fatty acids microemulsions with diesel oil and heating oil to give clean combustion and low particulate matter in the exhaust gases and flue gases.

[0014] A fourth objective is to utilize the esters of fatty acids in which the added advantages of a NOx scavenger and neutralization of the sulfur acids generated from the residual sulfur in the diesel fuel and in the heating oil are realized using the teachings of U.S. Pat. No. 6,017,368.

[0015] These objectives are achieved under a strict set of rules regarding the microemulsion fuels:

[0016] 1. The microemulsions containing the esters of fatty acids must be crystal clear at room temperature and have low viscosity for easy transport in fuel lines.

[0017] 2. The microemulsions must be stable and fluid at sub-freezing temperatures such as −15° C. Microemulsions may become cloudy or hazy at sub-freezing temperatures such as −15° C. but they must be uniform with no phase separation and fluid with low viscosity for easy transport in fuel lines. They must be free of any gels or solid formation. (Cloudiness and haze decrease as the sample is warmed from the temperature of −15° C. and the microemulsions clear between −6° and −1° C. The diesel oil control is hazy at −15° C. and clears at −6° C. when the sample is warmed).

[0018] The extent of the use of the esters of fatty acids depends on three fundamentals, namely, the unsaturated fatty acid used in preparing the Additive, the particular ester and the fuel composition.

PROCEDURE

[0019] The procedure is to first prepare the Additive for a target fuel composition using the teachings of U.S. Pat. No. 6,017,368. Then the ester of the fatty acid is dissolved in the Additive which gives a clear solution. Finally, the diesel oil or the heating oil is blended in at low shear to prepare the microemulsion. The fuel compositions investigated were 95/05, 90/10, 80/20, 70/30 and 60/40 weight to weight Diesel Oil/Additive plus the Ester.

[0020] The esters investigated were methyl stearate, ethyl stearate, butyl stearate, methyl palmitate, ethyl palmitate, methyl m yristate, ethyl myristate and the methyl ester CE-1618 of Procter & Gamble Chemicals. The latter is a methyl ester of a mixture of saturated and unsaturated fatty acids.

[0021] The unsaturated fatty acids used for the preparation of the Additives are oleic acid and Emersol 315 linoleic acid. It was dicovered that the results are very different with oleic acid versus Emersol 315 linoleic acid. The latter which is more unsaturated than oleic acid result in microemulsions containing much larger amounts of esters.

[0022] The method of determining the maximum amount of ester that can be used in a fuel composition is to continue experiments with larger and larger amounts of it in the formulations for a given Diesel Oil/Additive plus Ester composition until the test sample shows gels at −15° C. The result is that many experiments must be done to establish only one of the points of a curve such as in any of the curves shown in FIG. 1.

[0023] In order to compare each ester of a fatty acid on an equal basis, there are two characteristics that should be considered, namely, the amount of Additive and the alcohol group of the ester. The greater the amount of Additive and the larger the alcohol group, the greater the amount of ester in the microemulsion. Therefore, a way to equate each ester and equate each composition, is to use the percent ratio of the calculated parent fatty acid of the ester to the calculated total unsaturated fatty acid in the Addditive. Thus, when comparing methyl stearate with ethyl stearate, the amount of stearic acid from each is calculated. Then one can see the direct effect of the alcohol group of the ester on imparting dispersion of the ester in the microemulsion. Then by dividing this by the amount of total calculated unsaturated fatty acid in the Additive, gives all compositions on an equal basis for investigating the trends in going from 95/05 to 60/40 composition.

[0024] For example, if a microemulsion contains 2.00 grams of methyl stearate and another contains 2.00 grams of ethyl stearate, a direct comparison is to calculate the amount of stearic acid from each. The amount of stearic acid in 2.00 grams of methyl stearate is (2.00)(284.47/298.51) or 1.91 grams of stearic acid. The amount of stearic acid in 2.00 grams of ethyl stearate is (2.00)(284.47/312.54) or 1.82 grams.

[0025] This example shows that for given equal weights of 2.00 grams each of methyl stearate and ethyl stearate, the methyl group imparts (1.91−1.82=0.09 gram) more calculated stearic acid in the microemulsion than the ethyl group. By doing this all of the different esters investigated are directly compared in spite of the alcohol group of the ester. Another way of showing this is to calculate how much of an ester must be used to disperse a given amount of the calculated parent fatty acid. For example, how much methyl stearate and how much butyl stearate is needed to give 2.00 grams of calculated stearic acid? The amount of methyl stearate is (2.00)(298.51/284.47) or 2.10 grams and the amount of butyl stearate calculates to be (2.00)(340.59/284.47) or 2.39 grams. This means that 2.10 grams of methyl stearate is equivalent to 2.39 grams of butyl stearate to give the same amount of calculated stearic acid in the microemulsion.

[0026] The above calculations represent a direct comparison of the effect of the alcohol group of the ester in imparting dispersion of the ester in the microemulsion.

[0027] Compositions of 95/05, 90/10, 80/20, 70/30 and 60/40 weight to weight diesel oil/Additive plus ester were investigated. The method for determining the amount of loading of the ester in the microemulsion at a given composition is to calculate the percent ratio of the calculated fatty acid in the ester to the total amount of calculated unsaturated fatty acid in the Additive.

[0028] For example, when oleic acid is the unsaturated fatty acid in the Additive, there are three components from oleic acid in the Additive, namely, ammonium oleate, free oleic acid and sodium oleate. Knowing the composition of the Additive, one can calculate the total amount of oleic acid in a given weight of the Additive. Then knowing the amount of the ester that is used, the amount of the fatty acid in the ester can be calculated. The percent ratio of the fatty acid in the ester to the total oleic acid in the Additive is calculated.

[0029] Each level of a given ratio is investigated until the microemulsion fails the test at −15° C. in order to determine the maximum amount of each fatty acid ester that can be dispersed in the microemulsion at a given fuel composition. Thus, suppose that methyl stearate is being investigated in a 90/10 diesel oil/Additive plus Ester composition. If it is found that for a calculated percent ratio of stearic to oleic of 30%, the microemulsion is stable at −15° C., then 40% is tried. If the 40% gives a microemulsion that gels at −15° C., this, of course, is unacceptable. Then 35% is tried. If this is successful, the amswer is 35%. However, if 35% also causes gelation, then the answer is 30% loading of the methyl stearate for the 90/100 wt/wt diesel oil/Additive plus Ester.

[0030] In a similar manner, Emersol 315 linoleic acid was investigated at the 95/05, 90/10, 80/20, 70/30, and 60/40 compositions of wt/wt diesel oil/Additive plus Ester. It was discovered that the results for Emersol 315 linoleic acid were entirely different than those in which oleic acid was used in the Additive. The greater degree of unsaturation in the fatty acids of Emersol 315 linoleic acid compared to oleic acid significantly increased the amounts of each of the esters that could be dispersed in the microemulsions. So the investigations using oleic acid and Emersol 315 linoleic acid must be separate.

[0031] For oleic acid in the Additive and using diesel oil, the results are graphed in FIGS. 1 to 5. For Emersol 315 linoleic acid in the Additive and using diesel oil, the results are graphed in FIGS. 6 to 9. FIG. 10 represents methyl stearate with oleic acid in the Additive but using home heating oil instead of diesel oil.

[0032] The graphed results give a vivid picture of the behavior of each fatty acid ester in which the percent ratio of the calculated parent fatty acid of the ester to the calculated total unsaturated fatty acid of the Additive is plotted against the microemulsion composition. FIGS. 1 to 10 are described in detail under DISCUSSION OF RESULTS.

PREPARATION OF THE ADDITIVES

[0033] The fundamentals of Steinmann's U.S. Pat. No. 6,017,368 are used for preparing the Additives. The amounts of components for each composition used for small scale experiments are summarized in Table 1. TABLE 1 Preparation of the Additives Target Composition 95/05 90/10 80/20 70/30 60/40 Unsaturated 30.0 30.0 30.0 30.0 30.0 Fatty Acid, mls Octanol-1, mls 5.0 5.0 5.0 5.0 5.0 Surfynol 104A, mls 5.0 5.0 5.0 5.0 5.0 Methanol, mls 5.0 10.0 15.0 20.0 25.0 Added Water, mls 4.0 6.0 8.0 10.0 12.0 29.2% Aqueous 3.7 3.9 3.9 3.9 3.9 Ammonia, mls Na₂CO₃, gms 0.66 0.33 0.16 0.10 0.07 Ethyl Carbamate 5.24 2.79 2.51 2.24 1.87 or Urea, gms Specific Gravity 0.907 0.904 0.900 0.892 0.889 of the Additive at 25° C.

[0034] Procedure for Preparing the Additive:

[0035] The unsaturated fatty acid, octanol-1, Surfynol 104A, and the methanol are added together giving a clear solution. When urea is used as the NOx scavenger it is dissolved in the added water along with the sodium carbonate and the resulting solution added to the previous clear solution. The sodium carbonate reacts with the unsaturated fatty acid to give the sodium salt with evolution of carbon dioxide. At this point the solution is cloudy due to the added water. Then the aqueous ammonia is added which forms the ammonium salt of the unsaturated fatty acid. The solution becomes crystal clear and is fluid with a low viscosity.

[0036] When ethyl carbamate is used as the NOx scavenger, it is added after the aqueous ammonia is added.

[0037] Remarks on Table 1:

[0038] 1. This is the same procedure as described in U.S. Pat. No. 6,017,368.

[0039] 2. The unsaturated fatty acid used in this invention is oleic acid and Emersol 315 linoleic acid. Emersol 315 linoleic acid, from Cognis Canada Corporation, Toronto Plant, Toronto, Canada is comprised of 60% linoleic acid, 25% oleic acid, 9% linolenic acid, 4% palmitic acid, 1% stearic acid and 1% myristic acid. The results in this invention are completely different for oleic acid versus Emersol 315 linoleic acid, therefore, separate experiments must be used for each of the acids.

[0040] 3. For the 95/05 composition, only ethyl carbamate NOx scavenger is used. For the others, either ethyl carbamate or urea can be used.

[0041] 4. Surfynol 104A, from Air Products and Chemicals, Inc., Allentown, Pa. is a 50% solution by weight of a non-ionic surfactant dissolved in iso-octanol (2-ethylhexanol-1). The surfactant is an acetylenic diol with the formula 2,4,7,9-tetramethyl-5-decyne-4,7 diol.

[0042] 5. Octanol-1 alone as the non-ionic is also excellent and also, a blend of octanol-1 and iso-octanol such as 50/50 can be successfully used. The results for 100% iso-octanol are not nearly as good as the results for 50/50 octanol-1/Surfynol-104A and for 100% octanol-1 regarding the stability of the microemulsions at sub-freezing temperatures such as −15° C.

[0043] 6. Methanol can be replaced by methanol/ethanol, ethanol or isopropanol. Methanol gives the highest oxygen content which is desirable for complete combustion.

[0044] 7. The sodium carbonate neutralizes the sulfur acids generated from the oxidation of the residual sulfur in the diesel oil during combustion. The amount shown is for an assumed amount of 200 ppm of sulfur in the diesel oil. Of course, the stoichiometric amount is used for any given sulfur level.

[0045] 8. The ethyl carbamate and urea are NOx scavengers to reduce the level of this toxic gas in the exhaust.

[0046] 9. All of the Additives are clear, fluid solutions with easy transport characteristics.

[0047] 10. An important note is that the ratio of the unsaturated fatty acids to the methanol and also to the added water must be very high to make a stable microemulsion at the 95/05 composition. As the composition decreases in diesel oil toward 60/40 these ratios also decrease.

[0048] 11. The preparation of the Additives can be scaled up to any given amount. For example, to prepare 55 gallon drum batches, multiply the amounts shown in Table 1 by the following factors:

[0049] For 95/05-3603.

[0050] For 90/10-3366

[0051] For 80/20-3047

[0052] For 70/30-2766

[0053] For 60/40-2545

[0054] For these calculations use the following specific gravities: 0.9 for Oleic Acid or Emerssol 315 linoleic acid, 0.829 for octanol-1, 0.87 for Surfynol 104A, 0.792 for methanol, 1.0 for water, 0.9 for 29.2% aqueous ammonia and the measured specific gravity of the Additive. The CO₂ lost from the sodium carbonate is the weight used times 44/106.

[0055] The composition of the Additive using oleic acid and before the addition of the Fatty Acid Ester is shown in Table 2 for the compositions used. TABLE 2 Composition of the Additive with Oleic Acid Target Composition 95/05 90/10 80/20 70/30 60/40 Ammonium Oleate, % 32.68 32.29 29.08 26.89 24.83 Free Oleic Acid, % 13.98 14.65 14.64 14.02 13.18 Sodium Oleate, % 7.23 3.43 1.52 0.89 0.57 Octanol-1, % 7.91 7.41 6.68 6.18 5.70 Surfactant in 4.15 3.89 3.50 3.24 2.99 Surfynol 104A, % Solvent in 4.15 3.89 3.50 3.24 2.99 Surfynol 104A, % Methanol, % 7.56 14.16 19.15 23.59 27.23 Total Water, % 12.34 15.28 16.93 18.62 19.94 Ethyl Carbamate 10.00 5.00 5.00 3.33 2.57 or Urea, %

[0056] The compositions using Emersol 315 linoleic acid are shown in Table 3. They are slightly different because the molecular weight of Emersol 315 linoleic acid calculates to be 279.33 which is slightly less than that for oleic acid which is 282.47. TABLE 3 Composition of the Additive with Emersol 315 Linoleic Acid Target Composition 95/05 90/10 80/20 70/30 60/40 Ammonium Salts of 32.34 31.95 28.78 26.61 24.59 Emersol 315 Linoleic Acid, % Emersol 315 Linoleic 14.39 15.03 15.02 14.32 13.45 Free Acids, % Sodium Salts of 7.18 3.39 1.45 0.88 0.57 Emersol 315 Linoleic Acid, % Octanol-1, % 7.91 7.41 6.68 6.17 5.70 Surfactant in 4.15 3.89 3.50 3.24 2.99 Surfynol 104A, % Solvent in 4.15 3.89 3.50 3.24 2.99 Surfynol 104A, % Methanol, % 7.55 14.16 19.14 23.59 27.25 Total Water, % 12.34 15.28 16.93 18.62 19.95 Ethyl Carbamate 9.99 5.00 5.00 3.33 2.51 or Urea, %

PREPARATION OF MICROEMULSIONS CONTAINING ALKYL FATTY ACID ESTERS

[0057] To a given weight of the Additive, the weight of a specific alkyl fatty acid ester is dissolved in the Additive. Then this clear solution is blended with diesel oil at low shear to prepare the microemulsion fuel. The weights of Additives arbitrarily selected for each microemulsion composition are shown below.

[0058] For 95/05 composition, 4.43 grams.

[0059] For 90/10 composition, 9.33 grams.

[0060] For 80/20 composition, 12.60 grams.

[0061] For 70/30 composition, 15.00 grams

[0062] For 60/40 composition, 20.00 grams.

[0063] The alkyl fatty acid ester is dissolved in the Additive resulting in a crystal clear solution. (With certain esters such as methyl stearate slight warming of the solution is necessary to give the clear solution). To this solution is added the appropriate amount of diesel oil to prepare the microemulsion. The microemulsion is placed in the freezer at −15° C. at least overnight. It is then examined. Microemulsions must be fluid, uniform and free of any gels. They are hazy or cloudy at −15° C. like the diesel oil control, however, they become clear between −6° C. and −1° C. when warmed. Experiments are made to determine the maximum amount of the ester that can be dissolved in the microemulsion to satisfy the criterion of a fluid, uniform microemulsion free of any gels. (The worst condition of gelation is when the entire microemulsion solidifies into a soft solid. The unacceptable stage prior to this is the presence of gels dispersed in the microemulsion).

[0064] The objective in each investigation is to determine the percent ratio of the calculated parent acid in the ester to the total calculated unsaturated acid in the Additive for each microemulsion composition. The reason for this is for one to be able to compare directly the extent of utilization of each ester in the microemulsion. For each ratio for a given composition, two calculations are made. The first is the amount of unsaturated fatty acid in the Additive. The data of Tables 2 and 3 are used. Regarding Table 2, the amount of total oleic acid in an Additive comes from three sources, the ammonium oleate, the free oleic acid and the sodium oleate. The amount of oleic acid is calculated from the respective percentages shown in Table 2. For example, the 4.43 grams of Additive for the 95/05 composition contains a total of 2.28 grams of oleic acid calculated as follows:

[0065] Oleic acid from ammonium oleate equals:

[0066] (4.43)(0.3268)(282.47/299.50)=1.365 grams

[0067] Oleic acid from free oleic acid equals:

[0068] (4.43)(0.1398)=0.619 gram

[0069] Oleic acid from sodium oleate:

[0070] (4.43)(0.0723)(282.47/304.47)=0.297 gram

[0071] The total is 1.365+0.619+0.297=2.281 grams

[0072] Since all weighings are made to the nearest centigram, the total oleic acid is rounded-off to two decimal places giving 2.28 grams of calculated oleic acid in 4.43 grams of Additive for the 95/05 composition.

[0073] The other calculation is the amount of parent fatty acid of the fatty acid ester. For example, it was found that for the 95/05 composition in which 4.43 grams of Additive are used, 1.67 grams of methyl stearate is the maximum amount that can be used. The parent stearic acid is calculated as follows:

[0074] (1.67)(284.47/298.51)=1.59 grams.

[0075] The percent ratio of calculated stearic acid to calculated oleic acid is equal to (1.59/2.28)(100) or 69.74. This is rounded-off to 70%, the accuracy of the experiment being no better than 1%.

[0076] By calculating all of the data in this manner, one can have a direct comparison of the utilization of each fatty acid ester in the microemulsion fuel.

[0077] It turns out that since the data of Table 3 for Emersol 315 linoleic acid is close to the data of Table 2 for oleic acid, the calculations of the total Emersol 315 linoleic acid rounded-out to two decimal places is the same as that for oleic acid in each of the compositions.

DISCUSSION OF THE RESULTS EXAMPLE I

[0078] Comparison of Methyl Stearate and Ethyl Stearate with Oleic Acid in the Additive.

[0079] The data for methyl stearate-oleic Acid in the Additive are given in Tables 4 and 5. The data for ethyl stearate-oleic Acid in the Additive are given in Tables 6 and 7. TABLE 4 Microemulsions Containing Methyl Stearate with Oleic Acid in Each Additive Composition Target 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Stearate, gms 1.67 1.66 0.86 0.63 0.39 Diesel Oil, gms 115.90 98.91 53.84 36.47 30.59 Total Weight of 122.00 109.90 67.30 52.10 50.98 Microemulsion, gms. Specific Gravity 0.842 0.846 0.853 0.855 0.858 of Microemulsion at 25° C. Calc'd Total Oleic 2.28 4.51 5.48 6.03 7.43 Acid in Additive, gms Calc'd Stearic Acid in 1.59 1.58 0.82 0.60 0.37 Methyl Stearate, gms. Percent Ratio of 70 35 15 10 5 Calc'd. Stearic Acid to Calc'd. Oleic Acid

[0080] TABLE 5 Compositions of Microemulsions Containing Methyl Stearate with Oleic Acid in Each Additive Wt/Wt Diesel Oil/ADDITIVE Component plus Methyl Stearate 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Stearate, % 1.37 1.51 1.28 1.21 0.76 Amm. Oleate, % 1.19 2.74 5.45 7.75 9.73 Free Oleic Acid, % 0.51 1.25 2.73 4.03 5.18 Sodium Oleate, % 0.26 0.29 0.28 0.26 0.23 Octanol-1, % 0.29 0.63 1.25 1.79 2.24 Surfactant in 0.15 0.33 0.66 0.92 1.18 Surfynol 104A, % Solvent in 0.15 0.33 0.66 0.92 1.18 Surfynol 104A, % Methanol, % 0.28 1.21 3.59 6.79 10.67 Total Water, % 0.44 1.29 3.16 5.35 7.81 Ethyl Carbamate 0.36 0.42 0.94 0.980 1.02 or Urea, %

[0081] TABLE 6 Microemulsions Containing Ethyl Stearate with Oleic Acid in Each Additive Composition Target 95/05 90/10 80/20 70/30 60/40 Additive, gms. 4.43 9.33 12.60 15.00 20.00 Ethyl Stearate, gms. 2.00 2.98 2.11 1.33 1.22 Diesel Oil, gms. 122.17 110.79 58.84 38.10 31.83 Total Weight of 128.60 123.10 73.55 54.43 53.05 Microemulsion, gms Specific Gravity of 0.841 0.844 0.851 0.853 0.854 Microemulsion at 25° C. Calc'd. Total Oleic 2.28 4.51 5.48 6.03 7.43 Acid in Additive, gms Calc'd. Stearic Acid 1.82 2.71 1.92 1.21 1.11 in Ethyl Stearate, gms Percent Ratio of 80 60 35 20 15 Calc'd. Stearic Acid to Calc'd. Oleic Acid

[0082] TABLE 7 Compositions of Microemulsions Containing Ethyl Stearate with Oleic Acid in Each Additive wt/wt Diesel Oil/Additive Component plus Ethyl Stearate 95/05 90/10 80/20 70/30 60/40 Diesel oil, % 95.00 90.00 80.00 70.00 60.00 Ethyl Stearate, % 1.55 2.42 2.87 2.44 2.30 Ammonium Oleate, % 1.13 2.45 4.98 7.41 9.35 Free Oleic Acid, % 0.48 1.10 2.50 3.86 4.98 Sodium Oleate, % 0.25 0.26 0.26 0.25 0.23 Octanol-1, % 0.27 0.56 1.15 1.71 2.15 Surfactant in 0.15 0.30 0.60 0.88 1.13 Surfynol 104A, % Solvent in 0.15 0.30 0.60 0.88 1.13 Surfynol 104A, % Methanol, % 0.26 1.08 3.29 6.50 10.25 Total Water, % 0.42 1.15 2.89 5.13 7.50 Ethyl Carbamate 0.34 0.38 0.86 0.94 0.98 or Urea, %

[0083] The results of the percent ratio of the calculated fatty acid of the ester which is stearic acid to the calculated total oleic acid in the Additive versus the composition of diesel oil/Additive plus ester from Tables 4 and 6 are plotted in FIG. 1. The results show the significant effect of the alcohol group of the ester.

[0084] The larger ethyl group gives increased dispersion of the ester in the microemulsion. The reasons may be increased solubility characterstics and lower melting point for the ethyl ester.

[0085] The curves for methyl stearate and ethyl stearate decrease sharply as the composition changes from 95/05 toward 60/40 which shows that there is a greater tendency for gelation of the microemulsion with change in composition toward 60/40.

EXAMPLE II

[0086] Comparison of Butyl Stearate and the Methyl Ester CE-1618 of Procter and Gamble with Oleic Acid in the Additive.

[0087] The data for butyl stearate are given in Tables 8 and 9. The data for the methyl ester CE-1618 are given in Tables 10 and 11. TABLE 8 Microemulsions Containing Butyl Stearate with Oleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Butyl Stearate, gms 2.18 11.34 8.52 5.77 4.45 Diesel oil, gms 125.59 186.03 84.48 48.46 36.68 Total Weight of 132.20 206.70 105.60 69.23 61.13 Microemulsion, gms Specific Gravity of 0.839 0.844 0.846 0.848 0.854 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Oleic Acid in Additive, gms Calc'd. Stearic 1.82 9.47 7.12 4.82 3.72 Acid in Butyl Stearate, gms Percent Ratio of 80 210 130 80 50 Calc'd. Stearic Acid to Calc'd. Oleic Acid

[0088] TABLE 9 Compositions of Microemulsions Containing Butyl Stearate with Oleic Acid in the Additive Wt/Wt Diesel Oil/Additive Component plus Butyl Stearate 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Butyl Stearate, % 1.65 5.49 8.07 8.34 7.28 Ammonium Oleate, % 1.10 1.46 3.47 5.83 8.11 Free Oleic Acid, % 0.47 0.66 1.74 3.03 4.32 Sodium Oleate, % 0.24 0.15 0.17 0.20 0.20 Octanol-1, % 0.26 0.33 0.80 1.34 1.87 Surfactant in 0.14 0.18 0.42 0.69 0.98 Surfynol 104A, % Solvent in 0.14 0.18 0.42 0.69 0.98 Surfynol 104A, % Methanol, % 0.25 0.64 2.29 5.11 8.90 Total Water, % 0.41 0.69 2.02 4.03 6.51 Ethyl Carbamate 0.34 0.22 0.60 0.74 0.85 or Urea, %

[0089] TABLE 10 Microemulsions Containing the Methyl Ester CE-1618 with Oleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Ester 2.88 10.90 8.64 7.61 7.81 CE-1618, gms Diesel oil, gms 138.89 182.00 84.96 52.76 41.72 Total Weight of 146.20 202.30 106.20 75.37 69.53 Microemulsion, gms Specific Gravity of 0.824 0.843 0.846 0.848 0.852 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Oleic Acid in Additive, gms Calc'd. Fatty Acids 2.74 10.37 8.22 7.24 7.43 in Methyl ester CE-1618, gms Percent Ratio of 120 230 150 120 100 Calc'd. Fatty Acids to Oleic Acid

[0090] TABLE 11 Compositions of Microemulsions Containing the Methyl Ester CE-1618 with Oleic Acid in the Additive Wt/Wt Diesel Oil/Additive plus Methyl Ester CE-1618 Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Ester 1.97 5.39 8.14 10.09 11.23 CE-1618, % Ammonium Oleate, % 0.99 1.49 3.45 5.35 7.13 Free Oleic Acid, % 0.42 0.68 1.73 2.79 3.80 Sodium Oleate, % 0.22 0.16 0.18 0.18 0.17 Octanol-1, % 0.24 0.34 0.79 1.23 1.64 Surfactant in 0.13 0.18 0.42 0.64 0.87 Surfynol 104A, % Solvent in 0.13 0.18 0.42 0.64 0.87 Surfynol 104A, % Methanol, % 0.23 0.65 2.28 4.70 7.82 Total Water, % 0.37 0.70 2.00 3.70 5.72 Ethyl Carbamate 0.30 0.23 0.59 0.68 0.75 or Urea, %

[0091] The persent ratio of the calculated fatty acids from butyl stearate to the calculated total oleic acid in the Additive versus the composition of diesel oil/Additive plus ester from Table 8 and the percent ratio of the calculated fatty acids from the methyl ester of CE-1618 to the calculated total oleic acid in the Additive versus the composition of diesel oil/Additive plus ester from Table 10 are plotted in FIG. 2. The two curves are similar indicating that the influence of the butyl group is about as effective as the unsaturation in the fatty acids of CE-1618 regarding dispersion of the esters in the microemulsions. Both curves show an unusual behavior from the 95/05 to the 90/10 composition. There is a sharp increase. Since the exact behavior is not known it is represented by a dashed straight line. Between 90/10 and the 60/40 compositions the percent ratios decrease sharply for both curves tending to level off at the 60/40 composition. The curves show that there is a much greater tendency for gelation of the microemulsion as the composition changes toward 60/40.

[0092] Comparison of FIGS. 1 and 2 demonstrate how the larger butyl group has much more influence than the smaller methyl and ethyl groups in the stearate for dispersion of the ester in the microemulsion.

EXAMPLE III

[0093] Comparison of Methyl Palmitate and Ethyl Palmitate with Oleic Acid in the Additive.

[0094] The data for microemulsions containing methyl palmitate with oleic acid in each Additive are summarized in Tables 12 and 13. The data for microemulsions containing ethyl palmitate with oleic acid in each Additive are summarized in Tables 14 and 15. TABLE 12 Microemulsions Containing Methyl Palmitate with Oleic Acid in Each Additive. Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Palmitate, gms 1.93 2.85 2.31 1.91 1.57 Diesel Oil, gms 120.84 109.62 59.64 39.46 32.36 Total Weight of 127.20 121.80 74.55 56.37 53.93 Microemulsion, gms. Specific Gravity 0.841 0.842 0.849 0.853 0.856 of Microemulsion at 25° C. Calc'd. Total Oleic 2.28 4.51 5.48 6.03 7.43 Acid in Additive, gms Calc'd. Palmitic 1.83 2.71 2.19 1.81 1.49 Acid in Methyl Palmitate, gms Percent Ratio of 80 60 40 30 20 Calc'd. Palmitic Acid to Calc'd. Oleic Acid

[0095] TABLE 13 Compositions of Microemulsions Containing Methyl Palmitate with Oleic Acid in the Additive Wt/Wt Diesel Oil/Additive plus Methyl Palmitate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Palmitate, % 1.52 2.34 3.10 3.39 2.91 Ammonium Oleate, % 1.14 2.47 4.92 7.16 9.20 Free Oleic Acid, % 0.49 1.13 2.47 3.73 4.90 Sodium Oleate, % 0.25 0.26 0.25 0.24 0.22 Octanol-1, % 0.27 0.57 1.13 1.65 2.12 Surfactant in 0.15 0.30 0.59 0.85 1.11 Surfynol 104A, % Solvent in 0.15 0.30 0.59 0.85 1.11 Surfynol 104A, % Methanol, % 0.26 1.09 3.25 6.28 10.09 Total Water, % 0.42 1.16 2.86 4.95 7.38 Ethyl Carbamate 0.35 0.38 0.84 0.90 0.96 or Urea, %

[0096] TABLE 14 Microemulsions Containing Ethyl Palmitate with Oleic Acid in the Additive Composition Target 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Ethyl Palmitate, gms 2.15 5.50 4.86 3.68 2.88 Diesel Oil, gms 125.02 133.47 69.84 43.59 34.32 Total Weight of 131.60 148.30 87.30 62.27 57.20 Microemulsion, gms Specific Gravity 0.836 0.841 0.846 0.852 0.854 of Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Oleic Acid in Additive, gms Calc'd. Palmitic 1.94 4.96 4.38 3.32 2.60 Acid in Ethyl Palmitate, gms Percent Ratio of 85 110 80 55 35 Calc'd. Palmitic Acid to Calc'd. Oleic Acid

[0097] TABLE 15 Compositions of Microemulsions Containing Ethyl Palmitate with Oleic Acid in the Additive Wt/Wt Diesel Oil/Additive plus Ethyl Palmitate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Ethyl Palmitate, % 1.63 3.71 5.57 5.91 5.03 Ammonium Oleate, % 1.10 2.03 4.20 6.48 8.67 Free Oleic Acid, % 0.47 0.92 2.11 3.37 4.62 Sodium Oleate, % 0.24 0.21 0.22 0.22 0.21 Octanol-1, % 0.27 0.47 0.97 1.49 1.99 Surfactant in 0.14 0.25 0.50 0.77 1.05 Surfynol 104A, % Solvent in 0.14 0.25 0.50 0.77 1.05 Surfynol 104A, % Methanol, % 0.26 0.89 2.77 5.69 9.51 Total Water, % 0.41 0.96 2.44 4.48 6.96 Ethyl Carbamate 0.34 0.31 0.72 0.82 0.91 or Urea, %

[0098] The percent ratio of the calculated palmitic acid to the calculated oleic acid in each Additive is plotted against the composition of diesel oil/Additive plus Ester from Tables 12 and 14. The curves are shown in FIG. 3. Again, the larger ethyl group results in more loading than the methyl group which trend is similar to that of FIG. 1. For methyl palmitate, the loading decreases continuously from 80% at 95/05 composition to 20% at 60/40 composition. For ethyl palmitate, there is first the sharp increase from 85% at 95/05 to 110% at 90/10 composition and then the loading decreases to 35% at the 60/40 composition. The sharp increase from 95/05 t0 90/10 composition does not occur for methyl palmitate.

[0099] The comparison of the curves of FIG. 3 and FIG. 1 shows that there is more loading in the microemulsions with the palmitic esters compared to the stearic esters. This was expected because of the smaller chain length of palmitic acid compared to stearic acid.

EXAMPLE IV

[0100] Comparison of Methyl Myristate and Ethyl Myristate with Oleic Acid in the Additive.

[0101] The data for microemulsions in which the ester is methyl myristate and oleic acid is used in the Additive are shown in Tables 16 an 17. The data for microemulsions in which the ester is ethyl myristate with oleic Acid in the Additive are shown in Tables 18 and 19. TABLE 16 Microemulsions Containing Methyl Myristate with Oleic Acid in the Additive Composition Target 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Myristate, gms 2.06 5.24 6.10 5.44 4.73 Diesel Oil, gms 123.31 131.13 74.80 47.69 37.10 Total Weight of 129.80 145.70 93.50 68.13 61.83 Microemulsion, gms. Specific Gravity 0.841 0.843 0.852 0.853 0.855 of Microemulsion at 25° C. Calc'd. Total Oleic 2.28 4.51 5.48 6.03 7.43 Acid in Additive, gms Calc'd. Myristic 1.94 4.96 5.25 5.13 4.46 Acid in Methyl Myristate, gms Percent Ratio of 85 110 105 85 60 Calc'd. Myristic Acid to Calc'd. Oleic Acid

[0102] TABLE 17 Compositions of Microemulsions Containing Methyl Myristate with Oleic Acid in the Additive Wt/Wt Diesel Oil/Additive plus Methyl Myristate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Myristate, % 1.59 3.60 6.53 7.98 7.65 Ammonium Oleate, % 1.12 2.07 3.92 5.92 8.02 Free Oleic Acid, % 0.48 0.94 1.97 3.08 4.27 Sodium Oleate, % 0.24 0.22 0.20 0.20 0.20 Octanol-1, % 0.27 0.47 0.90 1.37 1.84 Surfactant in 0.14 0.25 0.47 0.70 0.97 Surfynol 104A, % Solvent in 0.14 0.25 0.47 0.70 0.97 Surfynol 104A, % Methanol, % 0.26 0.91 2.59 5.20 8.80 Total Water, % 0.42 0.97 2.28 4.10 6.44 Ethyl Carbamate 0.34 0.32 0.67 0.75 0.84 or Urea, %

[0103] TABLE 18 Microemulsions Containing Ethyl Myristate with Oleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Ethyl Myristate, gms 2.30 6.07 7.07 7.11 7.51 Diesel Oil, gms 127.87 138.60 78.68 51.59 41.27 Total Weight of 134.60 154.00 98.35 73.70 68.78 Microemulsion, gms Specific Gravity 0.838 0.842 0.844 0.847 0.852 of Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Oleic Acid in Additive, gms Calc'd. Myristic 2.05 5.41 5.48 6.03 7.43 Acid in Ethyl Myristate, gms Percent Ratio of 90 120 115 105 90 Calc'd. Myristic Acid to Calc'd. Oleic Acid

[0104] TABLE 19 Compositions of Microemulsions Containing Ethyl Myristate with Oleic Acid in the Additive Wt/Wt Diesel Oil/Additive plus Ethyl Myristate Component 95/05 90/10 80/20 70/30 60/40 Diesel oil, % 95.00 90.00 80.00 70.00 60.00 Ethyl Myristate, % 1.71 3.94 7.19 9.65 10.92 Ammonium Oleate, % 1.08 1.96 3.73 5.48 7.21 Free Oleic Acid, % 0.46 0.89 1.87 2.85 3.84 Sodium Oleate, % 0.24 0.20 0.19 0.18 0.17 Octanol-1, % 0.26 0.45 0.86 1.26 1.66 Surfactant in 0.14 0.24 0.45 0.65 0.87 Surfynol 104A, % Solvent in 0.14 0.24 0.45 0.65 0.87 Surfynol 104A, % Methanol, % 0.25 0.86 2.46 4.80 7.91 Total Water, % 0.40 0.92 2.16 3.79 5.79 Ethyl Carbamate 0.32 0.30 0.64 0.69 0.76 or Urea, %

[0105] The percent ratios of the calculated myristic Acid to the calculated oleic Acid in the Additive versus the composition of diesel oil/Additive plus ester from Table 16 for methyl myristate and from Table 18 for ethyl myristate are plotted in FIG. 4. The curves show that there is slightly more loading with ethyl myristate than methyl myristate as expected. The high loading is due to the shorter chain length of myristic acid which in fact, has more influence that the ethyl group versus the methyl group as proven by the similar loadings for the two esters.

[0106] The pronounced effect of chain length of the fatty acid on the loading of the ester in the microemulsion is demonstrated in FIG. 5 for the methyl esters of stearic, palmitic and myristic acids. The shorter the chain length the greater the loading of the ester in the microemulsion.

EXAMPLE V

[0107] Comparison of Methyl Stearate and Ethyl Stearate with Emersol 315 Linoleic Acid in the Additive.

[0108] The data are shown in Tables 20 and 21 for methyl stearate and Tables 22 and 23 for ethyl stearate in which the unsaturated fatty acid in the Additive is Emersol 315 linoleic Acid. TABLE 20 Microemulsions Containing Methyl Stearate with Emersol 315 Linoleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms. 4.43 9.33 12.60 15.00 20.00 Methyl Stearate, gms. 2.39 2.37 1.44 0.94 0.78 Diesel Oil, gms. 129.58 105.30 56.16 37.19 31.17 Total Weight of 136.40 117.00 70.20 53.13 51.95 Microemulsion, gms. Specific Gravity of 0.835 0.842 0.845 0.847 0.852 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Emersol 315 Linoleic Acid in Additive, gms. Calc'd. Stearic Acid 2.28 2.26 1.37 0.90 0.74 in Methyl Stearate, gms. Percent Ratio of 100 50 25 15 10 Calc'd. Stearic Acid to Calc'd. Emersol 315 Linoleic Acid

[0109] TABLE 21 Compositions of Microemulsions Containing Methyl Stearate with Emersol 315 Linoleic Acid in the Additives Wt/Wt Diesel Oil/Additive plus Methyl Stearate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Stearate, % 1.75 2.03 2.05 1.77 1.50 Ammonium Salts of 1.05 2.55 5.16 7.52 9.47 Emersol 315 Linoleic Acid, % Free Emersol 315 0.47 1.20 2.70 4.04 5.18 Linoleic Acids, % Sodium Salts of 0.23 0.27 0.26 0.25 0.22 Emersol 315 Linoleic Acid, % Octanol-1, % 0.26 0.59 1.20 1.74 2.19 Surfactant in 0.14 0.31 0.63 0.92 1.15 Surfynol-104A, % Solvent in 0.14 0.31 0.63 0.92 1.15 Surfynol 104A, % Methanol, % 0.24 1.13 3.43 6.66 10.49 Total Water, % 0.40 1.21 3.04 5.24 7.68 Ethyl Carbamate 0.32 0.40 0.90 0.94 0.97 or Urea, %

[0110] TABLE 22 Microemulsions Containing Ethyl Stearate with Emersol 315 Linoleic Acid in Each Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms. 4.43 9.33 12.60 15.00 20.00 Ethyl Stearate, gms. 3.25 3.97 2.41 1.66 1.22 Diesel Oil, gms. 145.92 133.00 60.04 38.87 31.83 Total Weight of 153.60 133.00 75.05 55.53 53.05 Microemulsion, gms. Specific Gravity of 0.833 0.841 0.846 0.850 0.852 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Emersol 315 Linoleic Acid in Additive, gms Calc'd. Stearic 2.96 3.61 2.19 1.51 1.11 Acid from Ethyl Stearate, gms. Percent Ratio of 130 80 40 25 15 Calc'd. Stearic Acid to Calc'd. Emersol 315 Linoleic Acid

[0111] TABLE 23 Composition of Microemulsions Containing Ethyl Stearate with Linoleic Acid in Each Additive Wt/Wt Diesel Oil/Additive plus Ethyl Stearate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Ethyl Stearate, % 2.12 2.99 3.21 2.99 2.30 Ammonium Salts of 0.93 2.24 4.84 7.19 9.27 Emersol 315 Linoleic Acid, % Free Emersol 315 0.41 1.06 2.52 3.87 5.07 Linoleic Acids, % Sodium Salts of 0.21 0.24 0.24 0.24 0.21 Emersol 315 Linoleic Acid, % Octanol-1, % 0.23 0.52 1.12 1.67 2.15 Surfactant in 0.12 0.27 0.59 0.87 1.13 Surfynol 104A, % Solvent in 0.12 0.27 0.59 0.87 1.13 Surfynol 104A, % Methanol, % 0.22 0.99 3.21 6.37 10.27 Total Water, % 0.36 1.07 2.84 5.03 7.52 Ethyl Carbamate 0.28 0.35 0.84 0.90 0.95 or Urea, %

[0112] The percent ratios of the calculated stearic acid to the calculated total Emersol 315 linoleic acid in each Additive versus the composition of diesel oil/Additive plus ester from Table 20 for methyl stearata and from Table 22 for ethyl stearate are plotted in FIG. 6. Both curves show a sharp decrease in loading of the ester in the microemulsion from the 95/05 to the 60/40 compositions. These results show the strong tendency for gelation of the microemulsion approaching the 60/40 composition. There is more loading with ethyl stearate than with methyl stearate as expected because of the larger ethyl group.

[0113] Comparison of FIGS. 1 and 6 show the significant effect of the more unsaturated fatty acid Emersol 315 linoleic acid than oleic acid on increasing the loading of the esters in the microemulsions.

EXAMPLE VI

[0114] Comparison of Butyl Stearate and the Methyl Ester CE-1618 with Emersol 315 Linoleic Acid in Each Additive.

[0115] Data for butyl stearate with Emersol 315 linoleic acid in each Additive are given in Tables 24 and 25. Data for the methyl ester CE-1618 with Emersol 315 linoleic acid in each Additive are given in Tables 26 and 27. TABLE 24 Microemulsions Containing Butyl Stearate with Emersol 315 Linoleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Butyl Stearate, gms 6.55 16.20 15.09 12.27 6.23 Diesel Oil, gms 208.62 229.77 110.76 63.63 39.35 Total Weight of 219.60 255.30 138.45 90.90 65.58 Microemulsion, gms Specific Gravity of 0.828 0.837 0.838 0.846 0.853 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.43 6.03 7.43 Emersol 315 Linoleic Acid, gms Calc'd. Stearic 5.47 13.54 12.60 10.25 5.20 Acid from Butyl Stearate, gms Percent Ratio of 240 300 230 170 70 Calc'd. Stearic Acid to Calc'd. Emersol 315 Linoleic Acid

[0116] TABLE 25 Compositions of Microemulsions Containing Butyl Stearate with Emersol 315 Linoleic Acid in Each Additive Wt/Wt Diesel Oil/Additive plus Butyl Stearate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Butyl Stearate, % 2.98 6.35 10.90 13.50 9.50 Ammonium Salt of 0.65 1.17 2.62 4.39 7.50 Emersol 315 Linoleic Acid, % Free Emersol 315 0.29 0.55 1.37 2.36 4.10 Linoleic Acid, % Sodium Salt of 0.14 0.12 0.13 0.14 0.17 Emersol 315 Linoleic Acid, % Octanol-1, % 0.16 0.27 0.61 1.02 1.74 Surfactant in 0.09 0.14 0.32 0.54 0.92 Surfynol 104A, % Solvent in 0.09 0.14 0.32 0.54 0.92 Surfynol 104A, % Methanol, % 0.15 0.52 1.74 3.89 8.31 Total Water, % 0.25 0.56 1.54 3.07 6.08 Ethyl Carbamate 0.20 0.18 0.45 0.55 0.76 or Urea, %

[0117] TABLE 26 Microemulsions Containing the Methyl Ester CE-1618 with Emersol 315 Linoleic Acid in Each Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Ester 6.48 16.12 16.13 12.68 7.81 CE-1618, gms Diesel Oil, gms 207.29 229.05 114.92 64.59 41.72 Total Weight of 218.20 254.50 143.65 92.27 69.53 Microemulsion, gms Specific Gravity of 0.831 0.833 0.839 0.845 0.852 Microemulsion at 25° C. Calc'd. Total 2.88 4.51 5.48 6.03 7.43 Emersol 315 Linoleic Acid, gms Calc'd. CE-1618 6.16 15.34 15.34 12.06 7.43 Acids from the Methyl Ester, gms Percent Ratio of 270 340 280 200 100 Calc'd. CE-1618 Acids to Calc'd. Emersol 315 Linoleic Acid

[0118] TABLE 27 Compositions of Microemulsions Containing the Methyl Ester of CE-1618 with Emersol 315 Linoleic Acid in each Additive Wt/Wt Diesel oil/Additive plus Ester Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Ester 2.97 6.33 11.23 13.74 11.23 CE-1618, % Ammonium salt of 0.66 1.17 2.52 4.33 7.08 Emersol 315 Linoleic Acid, % Free Emersol 315 Linoleic Acid, % 0.29 0.55 1.32 2.33 3.87 Sodium Salt of 0.14 0.12 0.13 0.14 0.16 Emersol 315 Linoleic Acid, % Octanol-1, % 0.16 0.27 0.58 1.00 1.64 Surfactant in 0.09 0.15 0.31 0.53 0.86 Surfynol 104A, % Solvent in 0.09 0.15 0.31 0.53 0.86 Surfynol 104A, % Methanol, % 0.15 0.52 1.68 3.83 7.84 Total Water, % 0.25 0.56 1.48 3.03 5.74 Ethyl Carbamate 0.20 0.18 0.44 0.54 0.72 or Urea, %

[0119] The percent ratios of the calculated ester fatty acid to the calculated total Emersol 315 linoleic acid in each Additive versus the composition of diesel oil/Additive plus ester for butyl stearate from Table 24 and for the methyl ester CE-1618 from Table 26 are plotted in FIG. 7. The large loading for butyl stearate in the microemulsion requiring another scale is due to the large butyl group in butyl stearate further enhanced by the unsaturation of the fatty acids in Emersol 315 linoleic acid. The large loading for the methyl ester CE-1618 in the microemulsion is due to the combination of the unsaturation of the fatty acids in the ester and the unsaturation of the fatty acids in Emersol 315 linoleic acid. The curves are similar giving the conclusion that the butyl group in butyl stearate ester is about as effective as the unsaturation of the fatty acids in the methyl ester CE-1618.

[0120] The curves decrease sharply again showing the importance of the composition regarding gelation of the microemulsions with a much greater tendency toward the 60/40 composition.

[0121] Comparison of FIGS. 2 and 7 show the significant effect of replacing oleic acid with the more unsaturated Emersol 315 linoleic acid in the Additive on increasing the loading of both esters in the microemulsions.

EXAMPLE VII

[0122] Comparison of Methyl Palmitate and Ethyl Palmitate with Emersol 315 Linoleic Acid in the Additive.

[0123] Data are given in Tables 28 and 29 for methyl palmitate and Tables 30 and 31 for ethyl palmitate in which Emersol 315 linoleic Acid is in each Additive. TABLE 28 Microemulsions Containing Methyl Pamitate with Emersol 315 Linoleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Palmitate, gms 2.65 6.66 2.31 1.59 1.57 Diesel oil, gms 134.52 143.91 59.64 38.71 32.36 Total Weight of 141.60 159.90 74.55 55.30 53.93 Microemulsion, gms Specific Gravity of 0.835 0.841 0.847 0.848 0.851 Microemulsion at 25° C. Calc'd. Total Emersol 2.28 4.51 5.48 6.03 7.43 315 Linoleic Acid in Additive, gms Calc'd. palmitic 2.51 6.31 2.19 1.51 1.49 Acid in Methyl Palmitate, gms Percent Ratio of 110 140 40 25 20 Calc'd. Palmitic Acid to Calc'd. Emersol 315 Linoleic Acid

[0124] TABLE 29 Compositions of Microemulsions Containing Methyl Palmitate with Emersol 315 Linoleic Acid in the Additive Wt/Wt Diesel Oil/Additive plus Methyl Palmitate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Palmitate, % 1.87 4.16 3.10 2.88 2.91 Ammonium Salt of 1.01 1.86 4.86 7.22 9.12 Emersol 315 Linoleic Acid, % Free Acids of 0.45 0.88 2.54 3.88 4.99 Emersol 315 Linoleic Acid, % Sodium Salt of 0.22 0.20 0.24 0.24 0.21 Emersol 315 Linoleic Acid, % Octanol-1, % 0.25 0.43 1.13 1.67 2.11 Surfactant in 0.13 0.23 0.59 0.88 1.11 Surfynol 104A Solvent in 0.13 0.23 0.59 0.88 1.11 Surfynol 104A, % Methanol, % 0.24 0.83 3.24 6.40 10.11 Total Water, % 0.39 0.89 2.86 5.05 7.40 Ethyl Carbamate 0.31 0.29 0.85 0.90 0.93 or Urea, %

[0125] TABLE 30 Microemulsions Containing Ethyl Palmitate with Emersol 315 Linoleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms. 4.43 9.33 12.60 15.00 20.00 Ethyl Palmitate, gms. 4.30 13.00 5.47 4.02 3.29 Diesel Oil, gms. 165.87 200.97 72.28 44.38 34.94 Total Weight of 174.60 223.30 90.35 63.40 58.23 Microemulsion, gms. Specific Gravity 0.836 0.840 0.842 0.846 0.850 of Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Emersol 315 Linoleic Acid in Additive, gms. Calc'd. Palmitic 3.88 11.72 4.93 3.62 2.97 Acid from Ethyl Palmitate, gms. Percent Ratio of 170 260 90 60 40 Calc'd. Palmitic Acid to Calc'd. Emersol 315 Linoleic Acid

[0126] TABLE 31 Compositions of Microemulsions Containing Ethyl Palmitate with Emersol 315 Linoleic Acid in Each Additive Wt/Wt Diesel Oil/Additive plus Ethyl Palmitate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Ethyl Palmitate, % 2.46 5.82 6.05 6.34 5.65 Ammonium Salt of 0.82 1.34 4.01 6.29 8.44 Emersol 315 Linoleic Acid, % Free Emersol 315 0.37 0.63 2.10 3.39 4.62 Linoleic Acids, % Sodium Salt of 0.18 0.14 0.20 0.21 0.20 Emersol 315 Linoleic Acids, % Octanol-1, % 0.20 0.31 0.93 1.46 1.96 Surfactant in 0.11 0.16 0.49 0.77 1.03 Surfynol 104A, % Solvent in 0.11 0.16 0.49 0.77 1.03 Surfynol 104A, % Methanol, % 0.19 0.59 2.67 5.58 9.36 Total Water, % 0.31 0.64 2.36 4.40 6.85 Ethyl Carbamate 0.25 0.21 0.70 0.79 0.86 or Urea, %

[0127] The percent ratio of palmitic Acid to Emersol 315 linoleic acid versus the composition of diesel Oil/Additive plus the ester for methyl palmitate from Tables 28 and for ethyl palmitate from Table 30 is plotted in FIG. 8. The differences between the curves for methyl palmitate versus ethyl palmitate show that the larger ethyl group significantly increases the loading for ethyl palmitate in the microemulsions. For both of the esters there is the sharp increase in the loading from 95/05 to the 90/10 compositions and then a sharp decrease from 90/10 to 60/40 with strong tendency for gelation at the 60/40 composition.

[0128] Comparison of FIGS. 3 and 8 shows the pronounced effect of replacing oleic acid with Emersol 315 Linoleic Acid in the Additive in which FIG. 8 even required another scale. This again shows that the more the unsaturation of the fatty acid in the Additive the greater the loading of the ester in the microemulsion.

EXAMPLE VIII

[0129] Comparison of Methyl Myristate and Ethyl Myristate with Emersol 315 Linoleic Acid in the Additive.

[0130] Data for methyl myristate are given in Tables 32 and 33. Data for ethyl myristate are given in Tables 34 and 35. TABLE 32 Microemulsions Containing Methyl Myristate with Emersol 315 Linoleic Acid in the Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms 4.43 9.33 12.60 15.00 20.00 Methyl Myristate, gms 3.39 14.38 10.47 5.76 4.73 Diesel oil, gms 148.58 213.39 92.28 48.44 37.10 Total Weight of 156.40 267.10 115.35 69.20 61.83 Microemulsion, gms Specific Gravity of 0.826 0.834 0.839 0.842 0.848 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Emersol 315 Linoleic Acid, gms Calc'd. Myristic 3.19 13.54 9.86 5.43 4.46 Acid from Methyl Myristate, gms Percent Ratio of 140 300 180 90 60 Calc'd. Myristic Acid to Calc'd. Emersol 315 Linoleic Acid

[0131] TABLE 33 Compositions of Microemulsions Containing Methyl Myristate with Emersol 315 Linoleic Acid in the Additive Wt/Wt Diesel oil/Additive plus Methyl Myristate Component 95/05 90/10 80/20 70/30 60/40 Diesel oil, % 95.00 90.00 80.00 70.00 60.00 Methyl Myristate, % 2.17 6.06 9.08 8.32 7.65 Ammonium Salt of 0.92 1.27 3.14 5.77 7.96 Emersol 315 Linoleic Acid, % Free Emersol 315 0.41 0.59 1.64 3.11 4.35 Linoleic Acid, % Sodium Salt of 0.20 0.13 0.16 0.19 0.18 Emersol 315 Linoleic Acid, % Octanol-1, % 0.22 0.29 0.73 1.34 1.84 Surfactant in 0.12 0.15 0.38 0.70 0.97 Surfynol 104A, % Solvent in 0.12 0.15 0.38 0.70 0.97 Surfynol 104A, % Methanol, % 0.21 0.56 2.09 5.11 8.82 Total Water, % 0.35 0.60 1.85 4.04 6.45 Ethyl Carbamate 0.28 0.20 0.55 0.72 0.81 or Urea, %

[0132] TABLE 34 Microemulsions Containing Ethyl Myristate with Emersol 315 Llinoleic Acid in Each Additive Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms. 4.43 9.33 12.60 15.00 20.00 Ethyl Myristate, gms. 5.38 17.22 12.31 7.44 5.84 Diesel oil, gms. 186.39 238.95 99.64 52.36 38.76 Total Weight of 196.20 265.50 124.55 74.80 64.60 Microemulsion, gms. Specific Gravity of 0.832 0.836 0.845 0.847 0.850 Microemulsion at 25° C. Calc'd. Total 2.28 4.51 5.48 6.03 7.43 Emersol 315 Linoleic Acid, gms. Calc'd. Myristic 4.79 15.34 10.96 6.63 5.20 Acid from Ethyl Myristate, gms. Percent Ratio of 210 340 200 110 70 Calc'd. Myristic Acid to Calc'd. Emersol 315 Linoleic Acid

[0133] TABLE 35 Compositions of Microemulsions Containing Ethyl Myristate with Emersol 315 Linoleic Acid in Each Additive Wt/Wt Diesel Oil/Additive plus Ethyl Myristate Component 95/05 90/10 80/20 70/30 60/40 Diesel Oil, % 95.00 90.00 80.00 70.00 60.00 Ethyl Myristate, % 2.74 6.48 9.88 9.95 9.04 Ammonium Salt of 0.73 1.12 2.91 5.34 7.61 Emersol 315 Linoleic Acid, % Free Emersol 315 0.32 0.53 1.52 2.87 4.16 Linoleic Acids, % Sodium Salt of 0.16 0.12 0.15 0.18 0.18 Emersol 315 Linoleic Acid, % Octanol-1, % 0.18 0.26 0.68 1.24 1.76 Surfactant in 0.10 0.14 0.35 0.65 0.93 Surfynol 104A, % Solvent in 0.10 0.14 0.35 0.65 0.93 Surfynol 104A, % Methanol, % 0.17 0.50 1.94 4.73 8.44 Total Water, % 0.28 0.54 1.71 3.73 6.17 Ethyl Carbamate 0.22 0.17 0.51 0.66 0.78 or Urea, %

[0134] The comparison of the percent ratio of myristic acid to Emersol 315 linoleic acid plotted against the composition of diesel oil/Additive plus ester for methyl myristate from Table 32 and for ethyl myristate from Table 34 is shown in FIG. 9. Both curves show a steep increase in loading from 95/05 to the 90/10 composition. Again there is the sharp decrease in the curves between the compositions of 90/10 and 60/40 which means that there is a greater tendency for gelation of the microemulsions from 90/10 to the 60/40 compositions. The curves are similar which indicates that the unsaturation of the fatty acid in the Additive has more influence than the methyl group versus the ethyl group.

[0135] The effect of replacing oleic acid with the more unsaturated fatty acid Emersol 315 linoleic acid is demonstrated by comparing FIGS. 4 and 9. FIG. 9 requires a higher scale because of the greater loadings. However, the results for the 60/40 composition are the same which shows the importance of the composition on the gelation of the microemulsion. This means that the more unsaturated fatty acid in the Additive does not have the pronounced effect at the compositions of 60/40 regarding resistance to gelation. This conclusion is the same as that which was found for methyl palmitate.

EXAMPLE IX Mixture of Methyl Stearate and Methyl Palmitate in the Same Microemulsion with Oleic Acid in the Additive.

[0136] The purpose of this investigation was to study the use of both methyl stearate and methyl palmitate in the same microemulsion. The 95/05 composition was investigated in which oleic acid was used in the Additive. The results are summarized as below.

[0137] Exp. 1-30% each of methyl stearate and methyl palmitate. Excellent. Microemulsion was very fluid and uniform at −15° C. Only hazy at −15° C. with clearing at −3° C.

[0138] Exp 2-35% each of methyl stearate and methyl palmitate. Excellent. Same results for the microemulsion as found under Exp. 1.

[0139] Exp. 3-40% each of methyl stearate and methyl palmitate. Excellent. Same results for the microemulsion as found under Exp. 1.

[0140] Exp. 4-45% each of methyl stearate and methyl palmitate. Unsatisfactory. Presence of small gels dispersed throughout sample at −15° C.

[0141] The answer is Exp. 3 with 40% each of methyl stearate and methyl palmitate dispersed in the microemulsion. The data are given in Tables 36 and 37. TABLE 36 Microemulsions Containing both Methyl Stearate and Methyl Palmitate with Oleic Acid in the Additive Target Composition 95/05 Additive, gms 4.43 Methyl Stearate, gms 0.95 Methyl palmitate, gms 0.95 Diesel Oil, gms 120.46 Total Weight of Microemulsion, gms 126.79 Specific Gravity of Microemulsion at 25° C. 0.838 Calc'd. Total Oleic Acid in Additive, gms 2.28 Calc'd. Stearic Acid from Methyl Stearate, gms 0.91 Calc'd Palmitic Acid from methyl Palmitate, gms 0.91 Percent Ratio of Calc'd. Stearic Acid to 40 Calc'd Oleic Acid Percent Ratio of Calc'd. Palmitic Acid to 40 Calc'd. Oleic Acid

[0142] TABLE 37 Composition of Microemulsion Containing a Mixture of Methyl Stearate and Methyl Palmitate with Oleic Acid in the Additive Wt/Wt Diesel Component Oil/Additive plus mixture of esters Composition 95/05 Diesel Oil, % 95.00  Methyl Stearate, % 0.75 Methyl Palmitate, % 0.76 Ammonium Oleate, % 1.14 Free Oleic Acid, % 0.49 Sodium Oleate, % 0.24 Octanol-1, % 0.28 Surfactant in Surfynol 104A, % 0.15 Solvent in Surfynol 104A, % 0.15 Methanol, % 0.26 Total Water, % 0.43 Ethyl Carbamate, % 0.35

[0143] This experiment verifies the expected result that a mixture of fatty acid esters can be used in the same microemulsion fuel.

EXAMPLE X Methyl Stearate—Heating Oil for Furnaces and with Oleic Acid in Each Additive

[0144] Although heating oil for furnaces is similar to diesel oil, there are some differences. For example, the specific gravity of heating oil was found to be significantly higher than that of diesel oil, 0.851 versus 0.833. Also, the control samples had slightly different behavior at sub-freezing temperatures. The heating fuel oil gave some flocculent precipitate at −15° C. but this disappeared as the sample was warmed giving complete clarity at −8° C. Also, when samples of microemulsions with heating oil and the fatty ester were warmed from −15° C. they did not go through a haze stage like samples with diesel oil although they were very fluid. Instead, they remained cloudy until clearing occurred.

[0145] Heating oil was investigated using methyl stearate as the fatty ester and with oleic acid in each additive. The purpose was to compare the dispersion of this ester in fuel oil for furnaces to the dispersion in diesel oil previously described under EXAMPLE 1 and in FIG. 1 for the dispersion of methyl stearate in microemulsions with oleic acid in each of the Additives.

[0146] The data for the microemulsions using heating oil for furnaces and containing methyl stearate with oleic acid in the Additive are given in Tables 38 and 39. TABLE 38 Microemulsions Containing Methyl Stearate with Oleic Acid in the Additive and Made with Heating Oil for Furnaces Target Composition 95/05 90/10 80/20 70/30 60/40 Additive, gms. 4.43 9.33 12.60 15.00 20.00 Methyl Stearate, gms. 1.91 2.60 1.44 0.94 0.78 Heating Oil, gms. 120.46 107.37 56.16 37.19 31.17 Total Weight of 126.80 119.30 70.20 53.13 51.95 Microemulsion, gms. Specific Gravity of 0.852 0.855 0.859 0.861 0.869 Microemulsion at 25° C. Calc'd. Total Oleic 2.28 4.51 5.48 6.03 7.43 Acid in Additive, gms. Calc'd. Stearic 1.82 2.48 1.37 0.90 0.74 Acid from Methyl Stearate, gms. Percent Ratio of 80 55 25 15 10 Calc'd. Stearic Acid to Calc'd. Oleic Acid

[0147] TABLE 39 Compositions of Microemulsions Containing Methyl Stearate and Made with Oleic Acid and Heating Oil for Furnaces Wt/Wt Heating Oil/Additive plus Methyl Stearate Component 95/05 90/10 80/20 70/30 60/40 Heating Oil, % 95.00 90.00 80.00 70.30 60.00 Methyl Stearate, % 1.51 2.18 2.05 1.77 1.50 Ammonium Oleate, % 1.14 2.52 5.22 7.59 9.55 Free Oleic Acid, % 0.49 1.15 2.62 3.95 5.08 Sodium Oleate, % 0.24 0.26 0.27 0.25 0.23 Octanol-1, % 0.28 0.58 1.20 1.75 2.19 Surfactant in 0.15 0.31 0.63 0.91 1.16 Surfynol 104A, % Solvent in 0.15 0.31 0.63 0.91 1.16 Surfynol 104A, % Methanol, % 0.26 1.11 3.45 6.66 10.47 Total Water, % 0.43 1.19 3.03 5.25 7.66 Ethyl Carbamate 0.35 0.39 0.90 0.96 1.00 or Urea, %

[0148] The percent ratio of stearic acid to oleic acid versus the composition of heating oil/Additive plus methyl stearate from Table 38 is plotted in FIG. 10. The curve is similar to that for methyl stearate in FIG. 1 where diesel oil was used. The conclusion is that heating oil for furnaces used in microemulsions containing the esters of fatty acids gives similar results to diesel oil used in microemulsions containing the esters of fatty acids. 

I claim:
 1. A composition of matter made by dissolving an alkyl ester of a fatty acid in an Additive to give a clear solution and blending this solution with diesel oil or home heating oil to give a clear, low viscosity microemulsion fuel stable over a wide range of temperatures including sub-freezing temperatures like −15° C. whereby the microemulsion remains fluid with low viscosity and free of gels, with said Additive consisting of an unsaturated fatty acid partially neutralized with ammonia, a water-insoluble alkyl alcohol melting below 0° C., a non-ionic surfactant, a water-soluble alkyl alcohol, water, sodium salt of the unsaturated fatty acid and a NOx scavenger. 2 claim 1 in which the unsaturated fatty acid in the Additive is oleic acid and is neutralized with ammonia from about 60 to 70 mol percent.
 3. Claim 1 in which a mixture of unsaturated fatty acids predominant in linoleic acid containing less than 10% saturated fatty acids such as Emersol 315 Linoleic Acid is used and neutralized with ammonia from about 60 to 70 mol percent.
 4. Claim 1 in which the microemulsion fuel is defined as Petroleum Product/Additive plus Fatty Ester with percent ratios ranging from 95/05 to 60/40 weight/weight measured at compositions of 95/05, 90/10, 80/20, 70/30 and 60/40, the extent of the dispersibility of the fatty ester being expressed as a percent ratio of the calculated fatty acid in the ester to the total calculated unsaturated fatty acid in the Additive.
 5. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and methyl stearate is the fatty ester with maximum percent ratios of 70% for 95/05, 35% for 90/10, 15% for 80/20, 10% for 70/30 and 5% for 60/40.
 6. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and methyl palmitate is the fatty ester with maximum percent ratios of 80% for 95/05, 60% for 90/10, 40% for 80/20, 30% for 70/30 and 20% for 60/40.
 7. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and methyl myristate is the fatty ester with maximum percent ratios of 85% for 95/05, 110% for 90/10, 105% for 80/20, 85% for 70/30 and 60% for 60/40.
 8. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and ethyl stearate is the fatty ester with maximum percent ratios of 80% for 95/05, 60% for 90/10, 35% for 80/20, 20% for 70/30 and 15% for 60/40.
 9. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and ethyl palmitate is the fatty ester with maximum percent ratios of 85% for 95/05, 110% for 90/10, 80% for 80/20, 55% for 70/30 and 35% for 60/40.
 10. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and ethyl myristate is the fatty ester with maximum percent ratios of 90% for 95/05, 120% for 90/10, 115% for 80/20, 105% for 70/30 and 90% for 60/40.
 11. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and butyl stearate is the fatty ester with maximum percent ratios of 80% for 95/05, 210% for 90/10, 130% for 80/20, 80% for 70/30 and 50% for 60/40.
 12. Claims 2 and 4 in which the petroleum product is diesel oil or furnace heating oil and the methyl ester CE-1618 is the fatty ester with maximum percent ratios of 120% for 95/05, 230% for 90/10, 150% for 80/20, 120% for 70/30 and 100% for 60/40.
 13. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and methyl stearate is the fatty ester with maximum percent ratios of 100% for 95/05, 50% for 90/10, 25% for 80/20, 15% for 70/30 and 10% for 60/40.
 14. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and methyl palmitate is the fatty ester with maximum percent ratios of 110% for 95/05, 140% for 90/10, 40% for 80/20, 25% for 70/30 and 20% for 60/40.
 15. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and methyl myristate is the fatty ester with maximum percent ratios of 140% for 95/05, 300% for 90/10, 180% for 80/20, 90% for 70/30 and 60% for 60/40.
 16. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and ethyl stearate is the fatty ester with maximum percent ratios of 130% for 95/05, 80% for 90/10, 40% for 80/20, 25% for 70/30 and 15% for 60/40.
 17. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and ethyl palmitate is the fatty ester with maximum percent ratios of 170% for 95/05, 280% for 90/10, 90% for 80/20, 60% for 70/30 and 40% for 60/40.
 18. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and ethyl myristate is the fatty ester with maximum percent ratios of 210% for 95/05, 340% for 90/10, 200% for 80/20, 110% for 70/30 and 70% for 60/40.
 19. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and butyl stearate is the fatty ester with maximum percent ratios of 240% for 95/05, 300% for 90/10, 230% for 80/20, 170% for 70/30 and 70% for 60/40.
 20. Claims 3 and 4 in which the petroleum product is diesel oil or furnace heating oil and the methyl ester CE-1618 is the fatty ester with maximum percent ratios of 270% for 95/05, 340% for 90/10, 280% for 80/20, 200% for 70/30 and 100% for 60/40.
 21. Claims 1 in which the fatty ester comprises a mixture of saturated fatty esters.
 22. Claim 1 in which the fatty ester comprises a mixture of unsaturated fatty esters.
 23. Claim 1 in which the fatty ester comprises a mixture of saturated and unsaturated fatty esters. 